The agency is an administrative tribunal. Consequently, regardless of the wording used in the act, the agency cannot exercise its discretion and decide not to deal with a complaint. The provisions of the Transportation Act respecting the powers of the agency do not stipulate that the agency must review complaints. The agency is a tribunal, which means that when it receives a complaint, it is judicially obligated to take note of the complaint and to act on it.
What you're saying is true, but if you're concerned that for whatever reason, the agency does not deal with certain complaints, then I can tell you that this is not the case. In my estimation, that concern is unfounded. As an administrative tribunal, the agency is obligated to take note of all complaints filed and to take steps to address them.